Change TestBpfMap to use ConcurrentHashMap

IBpfMap#forEach allows concurrent map access (deleting from the map
while iterating), so we should allow this in TestBpfMap as well.

Test: builds
Change-Id: I89dc7e4daf1d0cfc1aac57cad4ea7f1e50f5f20c
diff --git a/staticlibs/testutils/devicetests/com/android/testutils/TestBpfMap.java b/staticlibs/testutils/devicetests/com/android/testutils/TestBpfMap.java
index 73bc3a9..3883511 100644
--- a/staticlibs/testutils/devicetests/com/android/testutils/TestBpfMap.java
+++ b/staticlibs/testutils/devicetests/com/android/testutils/TestBpfMap.java
@@ -24,11 +24,11 @@
 import com.android.net.module.util.IBpfMap.ThrowingBiConsumer;
 import com.android.net.module.util.Struct;
 
-import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.NoSuchElementException;
 import java.util.Objects;
+import java.util.concurrent.ConcurrentHashMap;
 
 /**
  *
@@ -42,7 +42,7 @@
  * @param <V> the value type
  */
 public class TestBpfMap<K extends Struct, V extends Struct> extends BpfMap<K, V> {
-    private final HashMap<K, V> mMap = new HashMap<K, V>();
+    private final ConcurrentHashMap<K, V> mMap = new ConcurrentHashMap<>();
 
     public TestBpfMap(final Class<K> key, final Class<V> value) {
         super(key, value);